This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Our long-term objectives of this proposal are to study the role of Elk-1 in growth and tumorigenicity of human prostate cancer cells. We have proposed the following specific aims: 1) Studies focused on testing the role of Elk-1 in suppressing the tumorigenicity of human prostate cancer cells. a. Develop stable PC-3 cell lines expressing Elk-1 proteins. b. Study expression of Elk-1, p21 and growth rate of PC-3 Elk-1 transfectants. c. Study invitro growth in soft agar. d. Study in vivo tumorigenicity in nude mice. 2) Studies directed towards testing the role of Elk-1 in the regulation of p21WAF1/CIP1 in human prostate cancer cell